The purpose of this article is to study the evolution of Xujiaweizi rift depression in Songliao Basin and then anylysis its control on the accumulation of natural gas，so it is necessary to know how active faults controlled sedimentary, reservoir reconstruction and caprock preservation.We take geological period first into consideration to classify function of fault controlling reservoir,and use the maximum throw subtracting method to research Xuxi fault.Xuxi fault was composed of several single faults and not the whole fault in Huoshiling Stage,and connected the whole fault in Shahezi Stage.The east branch fault of Xudong strike slip fault belt was active in Huoshiling Stage and Shahezi Stage,playing similar role in rift controlling as Xuxi fault,and involved in strike slip in Yingcheng Stage.Because fault dense zones on T2 reflecting layer were controlled by pre existing faults in rift stage, reactivation of pre existing faults can be recognized by the relationship between pre existing faults and fault dense zones,so we can find out which faults are gas source faults and which faults destroyed gas reservoirs.According to the stages of structure evolution,functions of fault controlling reservoir in Xujiaweizi fault depression can be divided into several categories: faulting in the rift stage controlled sedimentary of reservoir rock and source rock,which deposit in hangingwall of strongly active faults that had relative large peleo displacement;volcanic rock of Yingcheng Formation erupted along Xuzhong fault and Xudong Fault belt in order to form dominant volcanic facies;faults on T41 reflecting layer partly reactived,forming a lot of fractures to improve property of volcanic reservoir and being gas source faults,and it has feature like simultaneous reservoir formation and gas migration,and neighbourhood between advantageous reservoir and gas source faults,that benefited gas formation;most reserviors wasn`t destroyed in later stage because of weak faulting in northern and middle part of Xujiaweizi fault depression.So we present combined reservior pattern of “gas source faults and volcanic vents”.The several large scale faults including Xuxi fault,Xuzhong fault and Xudong,had multiple functions of reservoir controlling,and even the same fault has different function in every stage.